Children do not automatically inherit from their non-biological parents.
Greece's parliament was set to legalise same-sex marriage and adoption on Thursday, a landmark reform promoted by the conservative government over the opposition of the country's powerful Orthodox Church.
Dozens of ruling New Democracy party legislators are expected to oppose the bill in a vote late Thursday. But support from opposition parties means it is certain to pass.
The vote has been hailed as historic by LGBTQ associations, who said same-sex families face a labyrinth of administrative challenges amounting to discrimination under present family law.
When their children fall ill in Greece, non-biological parents currently have no right to decide what medical procedures are necessary for them.
Children do not automatically inherit from their non-biological parents.
If a child has two fathers, they can only be registered with the civil registry and covered by social services by entering the name of the biological mother.
And if the biological parent dies, the state can take away children from the other parent.
- Church 'totally opposed' -
Greece will become the first Orthodox Christian country, the 17th EU state and the 37th country in the world to legalise adoption by same-sex families.
The bill is expected to split Prime Minister Kyriakos Mitsotakis's conservative New Democracy party, with dozens of the party's 158 lawmakers likely to oppose it or abstain.
However, the bill is sure to pass with the support of the main opposition leftist Syriza party, whose leader Stefanos Kasselakis is gay, the socialist Pasok party and other smaller parties.
A simple majority in the 300-member parliament vote is needed for the bill to pass.
The Church of Greece -- which has close ties to many government MPs -- has said it is "totally opposed" to the reform, arguing that it "condemns" children to grow up in an "environment of confusion".
The head of the church Archbishop Ieronymos slammed the proposed law as part of a bid to impose a "new reality that seeks only to corrupt the homeland's social cohesion".
Some 4,000 people demonstrated in Athens against the measure on Sunday.
Kasselakis, who married his partner in a US ceremony in October, has been subjected to homophobic insults, most recently from a central Greece mayor and an island group governor.
Mitsotakis, who is personally championing the bill, was careful to stress last month that the changes would benefit just "a few children and couples".
The conservative leader, who comfortably won re-election in June, had promised to enact the reform during his second four-year term.
He announced it in January, just days after Kasselakis said Syriza would submit their own proposals for equality in marriage.
- 'Day of joy' -
Greek LGBTQ families, who had maintained a low profile since the reform was unveiled last month, have called for a celebratory gathering in Athens on Thursday.
"This is a day of joy," Rainbow Families Greece, an NGO helping LGBTQ families, said on Facebook.
"We will play with our children, and 'clean off' all the mud we have sustained all these years regarding who we are," the group said.
Same-sex couples will still not be able to use assisted reproduction or a surrogate mother, procedures reserved for single women or heterosexual couples who have trouble conceiving.
Greece had been condemned for anti-gay discrimination by the European Court of Human Rights in 2013, after gay couples were excluded from a 2008 civil uni.
Opinion polls indicate that a majority of Greeks support same-sex marriage but oppose surrogacy.
Under the Greek constitution, single parents, regardless of gender, have been allowed to adopt since 1946 -- but until now the second partner in a same-sex union was left out of the process.
Under the previous Syriza government, Greece in 2015 legalised civil unions for same-sex couples, becoming one of the last countries in the European Union to grant such approval.
That law had resolved property and inheritance issues, but made no provision for the adoption of children.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)